Distances per degree of longitude, for the latitudes marked in the picture.

Difference of longitudes

Actual distances

at 0° lat.

at 30° lat.

at 60° lat.

at 87.5° lat.

0.010 00 °

~ 1 000 m

~ 870.00 m

~ 500.0 m

~ 43.62 m

0.001 00 °

~ 0 100 m

~ 087.00 m

~ 050.0 m

~ 04.36 m

0.000 10 °

~ 0 010 m

~ 008.70 m

~ 005.0 m

~ 00.44 m

0.000 01 °

~ 0 001 m

~ 000.87 m

~ 000.5 m

~ 00.04 m

Variation with latitude of represented distances (in degrees or pixels) on the Mercator projection per actual distances (in meters) on Earth surface.

Level

# Tiles

Tile width (° of longitudes)

m / pixel (on Equator)

~ Scale (on screen)

Examples of areas to represent

00

000 000 000 001

360.0000

156 412.000

1:500 million

whole world

01

000 000 000 004

180.0000

078 206.000

1:250 million

02

000 000 000 016

090.0000

039 103.000

1:150 million

subcontinental area

03

000 000 000 064

045.0000

019 551.000

1:70 million

largest country

04

000 000 000 256

022.5000

009 776.000

1:35 million

05

000 000 001 024

011.2500

004 888.000

1:15 million

large African country

06

000 000 004 096

005.6250

002 444.000

1:10 million

large European country

07

000 000 016 384

002.8130

001 222.000

1:4 million

small country, US state

08

000 000 065 536

001.4060

000 610.984

1:2 million

09

000 000 262 144

000.7030

000 305.492

1:1 million

wide area, large metropolitan area

10

000 001 048 576

000.3520

000 152.746

1:500 thousand

metropolitan area

11

000 004 194 304

000.1760

000 076.373

1:250 thousand

city

12

000 016 777 216

000.0880

000 038.187

1:150 thousand

town, or city district

13

000 067 108 864

000.0440

000 019.093

1:70 thousand

village, or suburb

14

000 268 435 456

000.0220

000 009.547

1:35 thousand

15

001 073 741 824

000.0110

000 004.773

1:15 thousand

small road

16

004 294 967 296

000.0050

000 002.387

1:8 thousand

street

17

017 179 869 184

000.0030

000 001.193

1:4 thousand

block, park, addresses

18

068 719 476 736

000.0010

000 000.596

1:2 thousand

some buildings, trees

19

274 877 906 944

000.0005

000 000.298

1:1 thousand

local highway and crossing details

The "# Tiles" column indicates the number of tiles needed to show the entire world at the given zoom level. This is useful when calculating storage requirements for pre-generated tiles.

The "° Tile width" column gives the map width in degrees of longitude, for a square tile drawn at that zoom level.

Values listed in the column "m / pixels" gives the number of meters per pixel at that zoom level. These values for "m / pixel" are calculated with an Earth radius of 6372.7982 km and hold at the Equator; for other latitudes the values must be multiplied by the cosine (approximately assuming a perfect spheric shape of the geoid) of the latitude.

"~ Scale" is only an approximate size comparison and refers to distances on the Equator. In addition, the given scales assume that 256-pixel wide tiles are rendered and will be dependent on the resolution of the viewing monitor: these values are for a monitor with a 0.3 mm / pixel (85.2 pixels per inch or PPI). Such scale is typically used for the kind of area to represent on a single tile (Note that when rendering on the web, the standard CSS pixel size is defined at 96 PPI, browsers will rescale the images when needed but only by integer factors on PNG images to avoid making the rentered text or icons too fuzzy; if the screen has a lower resolution, the rendered images may be larger; and it's possible for a renderer to create image with other resolutions than 256 pixels at 96 PPI to better fit the expected sizes, and for a web interface to automatically select other available resolutions for Hi-DPI screens, but this requires more storage and computing resources on the server; as well the zoom level in the formulas above do not necessarily need to be integers, and this may be used to get intermediate scales with tiles having more pixels).

Distance per pixel math

The horizontal distance represented by each square tile, measured along the parallel at a given latitude, is given by:

As tiles are 256-pixels wide, the horizontal distance represented by one pixel is:

Spixel = Stile / 256 = C ∙ cos(latitude) / 2 (zoomlevel + 8)

For example on the equator and at zoom level 0, we get 40 075 016.686 / 256 ≈ 156 543.03 (in meters per pixel).

Make sure your calculator is in degrees mode, unless you want to express latitude in radians for some reason. C should be expressed in whatever scale unit you're interested in (miles, meters, feet, smoots, whatever).

This formula assumes that the Earth is perfectly spheric, but since the Earth is actually ellipsoidal there will be a slight error in this calculation, which does not take into account the flattening (with a slight reduction of radius for the best-fitting sphere passing at geographic poles at average sea level). But this error is very slight: it is null on the reference Equator, then grows to an absolute maximum of 0.3% at median latitudes, then shrinks back to zero at high latitudes towards poles.

The error also does not take into account additional differences caused by variation of the altitude on ground, or by the irregular variations of the geographic polar axis, and other errors caused by celestial tidal effects and climatic effects on the average sea level, or by continent drifts, major earthquakes, and magmatic flows below the crust).